The GOP is also vowing to get artists' permission before using musicians' work in future political campaigns.

The apology and pledge were released Tuesday along with an announcement of a settlement with Browne over a federal copyright infringement lawsuit filed last year in Los Angeles. Browne sued McCain and the national and Ohio Republican parties for using part of his song "Running on Empty" to mock Democrat Barack Obama's proposed energy policies in a web ad.

Financial details of the settlement weren't disclosed.

The statement said McCain didn't know about the ad, which was created by the Ohio Republican Party and removed after Browne complained.

"We apologize that a portion of the Jackson Browne song 'Running on Empty' was used without permission," said a statement attributed to McCain and the state and national parties.

McCain's campaign ran afoul of several musicians during his presidential run, including the Foo Fighters, Heart and John Mellencamp.

Browne released "Running on Empty" -- the song and an album by the same name -- in 1977. According to the lawsuit, the album has sold more than 7 million copies.

The musician's suit stated that Browne was concerned that use of his music would cause people to conclude he was endorsing McCain, even though the 60-year-old singer is a self-described liberal.